1. Field of Invention
Certain bis(2,3-dibromopropyl carbonates) of tetrahalobisphenol A; their use as fire-retardants; polymeric compositions embodying the same.
2. Prior Art
This invention relates to novel compounds and to flame retardant polymer compositions containing the novel compounds.
Flame retardant polymeric materials are in great demand. To improve the flame retardant or flame-out property of a polymer so that it will not support combustion beyond a few seconds is an objective of the entire polymer and polymer-related industry.
In the art of thermoplastics, many materials have been suggested as additives for imparting fire-retardant properties. Many of these additives have been halogen-containing compounds and some have been successful in rendering thermoplastics fire-retardant. It would seem that to merely increase the amount of these known additives would be sufficient to achieve the desired flame-retardant property whereby flame-out would occur in a matter of only a few seconds. However, achievement of the desired flame-retardant property by using large quantities of known flame retardants results in diminution of the other desirable properties of the polymer. In many instances, increasing the amounts of known flame-retardant compounds does not improve the flame-out property of the polymer. Moreover, merely increasing the amount of halogen in a material does not result in improved fire- or flame-retardant properties. This merely increases cost, without any guarantee of improved fire-retardant effect. It is apparent that, for enhanced fire-retardant properties, specifically-tailored molecules are required, rather than merely more of the same retardant or additional halogen in an existing retardant, but just how such molecules should be tailored is not clear. Nevertheless it is clear that new fire-retardant materials are required and it would be most desirable to have not only an improved fire-retardant additive and polymer composition, but to have such an economic additive and composition whereby and wherein other desirable properties of the polymer are not seriously diminished by addition of the flame-retardant agent.